Fiber examples

Optical properties also provide useful stmcture information about the fiber. The orientation of the molecular chains of a fiber can be estimated from differences in the refractive indexes measured with the optical microscope, using light polarized in the parallel and perpendicular directions relative to the fiber axis (46,47). The difference of the principal refractive indexes is called the birefringence, which is illustrated with typical fiber examples as foUows. Birefringence is used to monitor the orientation of nylon filament in melt spinning (48). 

Fibers in which the basic chemical units have been formed by chemical synthesis, followed by fiber formation, are called synthetic fibers. Examples include nylon, carbon, boron fibers, organic fibers, ceramic fibers, and metallic fibers. Among all commercially available fibers, Kevlar fibers exhibit high strength and modulus. (Kevlar is a DuPont trademark for poly [p-phenylene diamine terephthalamide].) It is an aromatic polyamide (aramid) in which at least 85% of the... 

With regard to heterocyclic compounds as coupling components, the importance of the formerly widespread pyrazolone-, aminopyrazole-, and 4-hydroxy -quinolone-based yellow azo dyes has greatly diminished with the advent of the tinctorially superior and therefore more economical pyridone azo dyes. Only a few examples have survived and then only for special applications such as for dyeing of acetate fibers. Examples are C.I. Disperse Orange 56 and C.I. Disperse Yellow5. (for structure, see Section 3.2.5). 

Polyphenylene sulfide fibers are other group of inherently FR fibers. Example is Diofort (Diolen Industrial Fibers, the Netherlands). 

With few exceptions weight reduction of parts in mobile applications is good. However, the carbon-fiber example shows the situation can only be judged for the concrete case and application. 

The low-capacity blood supply to the type Ilb fibers (Example 13.21) may limit the amount of epinephrine available to bind to the receptors, but the operation of the phosphorylation amplification cascade more than compensates and rapidly leads to full activation of glycogen phosphorylase. 

Sheers shirs (ca. 1920) n. Transparent, lightweight fabrics of different constructions and yarns, especially those of silk and manufactured fibers. Examples are chiffons, some crepes, georgette, and voile. 

Often, forensic chemists produce scientific evidence that can be described as either inclusive or exclusive. Recall the red fiber example mentioned earlier in the chapter. In that example, successive classification based on analytical data demonstrated that the red fiber from a crime scene belonged to the same class as fibers from a suspect s red nylon jacket. This is an example of inclusive evidence The jacket is included in the population of items that could have been the source of the fiber in question. Had the fibers from the jacket been found to have a cross section different from that of the fiber found at the scene, they would have been exclusionary evidence The jacket could not have been the source. 

Pesticides have been applied in a variety of formulations onto soils and crops for the control of insects, noxious weeds, fungi, and other bioagents that interfere in the production of food and fiber. Examples of such formulations are dusts, suspensions prepared from solid powders, and suspensions prepared from concentrated liquid formulations. The formulations, however, can have some undesired effects in that the active ingredient in these preparations can easily move about to a non-target area. Dusts can easily be carried for long distances away from the field even in the slightest winds. Evaporation to the atmosphere can take place with both dusts and liquid suspensions sprayed onto fields. 

For this third generation of manufactured protein fibers, milk and soy beans are the two most important protein sources. Chicken feathers also are being widely used in the development. In addition to the common methods used in the first and second generations, many technical innovations have been applied to the production of these manufactured protein fibers. Examples include the use of biochemistry to modity the protein structure, the incorporation of synthetic polymers to improve the fiber strength and modulus, the formation of protein-based copolymers by chemical grafting, etc. 

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